/* ============================================================
   全国查税计算系统 - 全局样式
   主色: 深蓝 #0f2a4a / 品牌蓝 #1a56db / 亮蓝 #2563eb
   强调: 琥珀 #f59e0b
   ============================================================ */
:root {
  --primary: #1a56db;
  --primary-dark: #0f2a4a;
  --primary-light: #3b82f6;
  --accent: #f59e0b;
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #1f2937;
  --text-light: #6b7280;
  --border: #e5e7eb;
  --success: #16a34a;
  --danger: #dc2626;
  --warning: #d97706;
  --shadow: 0 1px 3px rgba(15, 42, 74, .08), 0 4px 16px rgba(15, 42, 74, .06);
  --radius: 10px;
  --header-h: 64px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "微软雅黑", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  font-size: 15px;
  padding-top: var(--header-h);
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.hidden { display: none !important; }

/* ---------- 顶部导航 ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  background: rgba(255, 255, 255, .96);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  backdrop-filter: blur(8px);
}
.site-header .container {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; color: var(--primary-dark); }
.brand-logo {
  width: 36px; height: 36px; border-radius: 9px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: #fff; display: flex; align-items: center; justify-content: center;
  font-size: 18px; font-weight: 800;
}
.brand small { display: block; font-size: 11px; font-weight: 400; color: var(--text-light); line-height: 1.2; }
.main-nav { display: flex; align-items: center; gap: 4px; flex: 1; justify-content: flex-end; flex-wrap: wrap; }
.main-nav a {
  padding: 8px 14px; border-radius: 8px;
  color: var(--text); font-size: 14px; font-weight: 500;
  transition: all .15s;
}
.main-nav a:hover { background: #eef2ff; color: var(--primary); text-decoration: none; }
.main-nav a.active { background: var(--primary); color: #fff; }
.nav-cta { margin-left: 8px; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 9px 20px; border-radius: 8px; border: 1px solid transparent;
  font-size: 14px; font-weight: 600; cursor: pointer;
  transition: all .15s; background: var(--primary); color: #fff; line-height: 1.4;
}
.btn:hover { opacity: .9; text-decoration: none; color: #fff; }
.btn-outline { background: transparent; border-color: var(--primary); color: var(--primary); }
.btn-outline:hover { background: #eef2ff; color: var(--primary); }
.btn-accent { background: var(--accent); }
.btn-lg { padding: 12px 28px; font-size: 16px; }
.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn-block { width: 100%; }

/* 汉堡菜单（移动端） */
.nav-toggle { display: none; background: none; border: none; font-size: 24px; cursor: pointer; color: var(--primary-dark); }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(135deg, #0f2a4a 0%, #163a6b 55%, #1a56db 100%);
  color: #fff; padding: 72px 0 64px; position: relative; overflow: hidden;
}
.hero::after {
  content: ""; position: absolute; right: -120px; top: -120px;
  width: 420px; height: 420px; border-radius: 50%;
  background: radial-gradient(circle, rgba(255,255,255,.12) 0%, transparent 70%);
}
.hero .container { position: relative; z-index: 1; }
.hero h1 { font-size: 40px; line-height: 1.25; margin-bottom: 16px; letter-spacing: .5px; }
.hero p.lead { font-size: 17px; color: #dbe4f5; max-width: 780px; margin-bottom: 28px; }
.hero .badges { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 30px; }
.badge {
  background: rgba(255,255,255,.14); border: 1px solid rgba(255,255,255,.25);
  padding: 6px 14px; border-radius: 999px; font-size: 13px; color: #eef2ff;
}
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.hero-metrics { display: flex; gap: 40px; margin-top: 44px; flex-wrap: wrap; }
.metric .num { font-size: 30px; font-weight: 800; color: #fff; }
.metric .label { font-size: 13px; color: #b7c7e8; }

/* ---------- 区块 ---------- */
.section { padding: 56px 0; }
.section-alt { background: #fff; border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }
.section-title { font-size: 28px; font-weight: 800; color: var(--primary-dark); margin-bottom: 8px; }
.section-sub { color: var(--text-light); margin-bottom: 32px; max-width: 720px; }
.section-head { text-align: center; margin-bottom: 40px; }
.section-head .section-title { margin-bottom: 10px; }
.section-head .section-sub { margin: 0 auto; }

/* ---------- 卡片 ---------- */
.card {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); border: 1px solid var(--border);
  padding: 24px; transition: transform .15s, box-shadow .15s;
}
.card.hoverable:hover { transform: translateY(-3px); box-shadow: 0 8px 24px rgba(15,42,74,.12); }
.card-icon {
  width: 48px; height: 48px; border-radius: 12px; margin-bottom: 14px;
  display: flex; align-items: center; justify-content: center; font-size: 24px;
  background: linear-gradient(135deg, #eef2ff 0%, #e0e7ff 100%);
}
.card h3 { font-size: 17px; margin-bottom: 8px; color: var(--primary-dark); }
.card p { color: var(--text-light); font-size: 14px; margin-bottom: 12px; }
.card .card-link { font-size: 14px; font-weight: 600; }
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* ---------- 表格 ---------- */
.table-wrap { overflow-x: auto; border-radius: var(--radius); border: 1px solid var(--border); background: #fff; }
table.data { width: 100%; border-collapse: collapse; font-size: 14px; }
table.data th, table.data td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border); }
table.data thead th { background: var(--primary-dark); color: #fff; font-weight: 600; white-space: nowrap; }
table.data tbody tr:nth-child(even) { background: #f8fafc; }
table.data tbody tr:hover { background: #eef2ff; }
table.data td.num, table.data th.num { text-align: right; font-variant-numeric: tabular-nums; }
table.data tfoot td { font-weight: 700; background: #eef2ff; }

/* ---------- 表单 / 计算器 ---------- */
.calc-layout { display: grid; grid-template-columns: 420px 1fr; gap: 24px; align-items: start; }
.calc-layout.full { grid-template-columns: 1fr; }
.control-group { margin-bottom: 16px; }
.control-group label { display: block; font-size: 13px; font-weight: 600; color: var(--primary-dark); margin-bottom: 6px; }
.control-group .hint { font-size: 12px; color: var(--text-light); margin-top: 4px; }
.input, .select, textarea.input {
  width: 100%; padding: 10px 12px; border: 1px solid var(--border);
  border-radius: 8px; font-size: 14px; background: #fff; color: var(--text);
  transition: border-color .15s, box-shadow .15s;
}
.input:focus, .select:focus, textarea.input:focus {
  outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(26,86,219,.12);
}
.input-unit { position: relative; }
.input-unit .unit { position: absolute; right: 12px; top: 50%; transform: translateY(-50%); color: var(--text-light); font-size: 13px; pointer-events: none; }
.input-unit .input { padding-right: 42px; }
.row-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.row-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 12px; }
.row-4 { display: grid; grid-template-columns: 1fr 1fr 1fr 1fr; gap: 12px; }

.fieldset { border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; margin-bottom: 16px; background: #fafbfe; }
.fieldset legend { font-size: 13px; font-weight: 700; color: var(--primary); padding: 0 8px; }

.checkbox-line { display: flex; align-items: center; gap: 8px; font-size: 14px; margin-bottom: 8px; cursor: pointer; }
.checkbox-line input { accent-color: var(--primary); width: 16px; height: 16px; }

/* ---------- Tab ---------- */
.tab-nav { display: flex; gap: 4px; flex-wrap: wrap; border-bottom: 2px solid var(--border); margin-bottom: 24px; }
.tab-nav button {
  border: none; background: none; padding: 12px 18px; font-size: 14px; font-weight: 600;
  color: var(--text-light); cursor: pointer; border-bottom: 3px solid transparent;
  margin-bottom: -2px; transition: all .15s; border-radius: 8px 8px 0 0;
}
.tab-nav button:hover { color: var(--primary); }
.tab-nav button.active { color: var(--primary); border-bottom-color: var(--primary); background: #f0f4ff; }
.tab-panel { display: none; animation: fadeIn .25s ease; }
.tab-panel.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* ---------- 结果面板 ---------- */
.result-panel {
  background: linear-gradient(160deg, #f8fafc 0%, #eef2ff 100%);
  border: 1px solid #dfe7fb; border-radius: var(--radius); padding: 20px;
}
.result-panel .kpi-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 12px; margin-bottom: 18px; }
.kpi {
  background: #fff; border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px; text-align: center;
}
.kpi .kpi-label { font-size: 12px; color: var(--text-light); margin-bottom: 4px; }
.kpi .kpi-value { font-size: 20px; font-weight: 800; color: var(--primary-dark); font-variant-numeric: tabular-nums; }
.kpi .kpi-value.ok { color: var(--success); }
.kpi .kpi-value.warn { color: var(--warning); }
.kpi .kpi-value.danger { color: var(--danger); }
.kpi .kpi-sub { font-size: 11px; color: var(--text-light); margin-top: 2px; }
.result-panel h4 { font-size: 15px; color: var(--primary-dark); margin: 16px 0 10px; }
.result-panel .tips { margin-top: 14px; padding: 12px 14px; background: #fffbeb; border: 1px solid #fde68a; border-radius: 8px; font-size: 13px; color: #92400e; }
.result-panel .notice { margin-top: 14px; padding: 12px 14px; background: #fef2f2; border: 1px solid #fecaca; border-radius: 8px; font-size: 13px; color: #991b1b; }
.result-panel .note { margin-top: 14px; padding: 12px 14px; background: #eff6ff; border: 1px solid #bfdbfe; border-radius: 8px; font-size: 13px; color: #1e40af; }

/* ---------- 对比表（单位提前 VS 平台） ---------- */
.compare-grid { display: grid; grid-template-columns: 1fr auto 1fr; gap: 16px; align-items: stretch; }
.compare-col { border-radius: var(--radius); padding: 20px; border: 1px solid var(--border); }
.compare-col.general { background: #fef2f2; }
.compare-col.platform { background: #eff6ff; }
.compare-vs { display: flex; align-items: center; justify-content: center; font-weight: 800; color: var(--text-light); }
.compare-col h4 { margin-bottom: 10px; font-size: 15px; }
.compare-col ul { padding-left: 18px; font-size: 13.5px; color: var(--text-light); }
.compare-col li { margin-bottom: 6px; }
.compare-col strong { color: var(--text); }

/* ---------- 提示条 ---------- */
.alert { padding: 14px 16px; border-radius: 8px; font-size: 14px; margin-bottom: 20px; }
.alert-warning { background: #fffbeb; border: 1px solid #fde68a; color: #92400e; }
.alert-info { background: #eff6ff; border: 1px solid #bfdbfe; color: #1e40af; }
.alert-danger { background: #fef2f2; border: 1px solid #fecaca; color: #991b1b; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--primary-dark); color: #b7c7e8; padding: 48px 0 24px; margin-top: 48px; }
.site-footer .container { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; }
.site-footer h5 { color: #fff; font-size: 15px; margin-bottom: 12px; }
.site-footer a { color: #b7c7e8; font-size: 13.5px; display: block; margin-bottom: 8px; }
.site-footer a:hover { color: #fff; }
.site-footer .brand { color: #fff; margin-bottom: 10px; }
.site-footer .copy { grid-column: 1 / -1; border-top: 1px solid rgba(255,255,255,.12); padding-top: 18px; font-size: 12.5px; text-align: center; color: #8fa3c8; }

/* ---------- 面包屑 ---------- */
.crumb { font-size: 13px; color: var(--text-light); margin-bottom: 20px; }
.crumb a { color: var(--primary); }

/* ---------- 页头横幅 ---------- */
.page-head { background: linear-gradient(135deg, #0f2a4a 0%, #1a56db 100%); color: #fff; padding: 44px 0 40px; }
.page-head h1 { font-size: 30px; margin-bottom: 8px; }
.page-head p { color: #dbe4f5; font-size: 15px; max-width: 800px; }

/* ---------- FAQ / 折叠 ---------- */
details.faq { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 20px; margin-bottom: 12px; }
details.faq summary { font-weight: 600; cursor: pointer; color: var(--primary-dark); }
details.faq[open] summary { margin-bottom: 10px; }
details.faq p { font-size: 14px; color: var(--text-light); }

/* ---------- 法规引用 ---------- */
.law-item { background: #fff; border-left: 4px solid var(--primary); border-radius: 0 8px 8px 0; padding: 14px 18px; margin-bottom: 14px; box-shadow: var(--shadow); }
.law-item h4 { color: var(--primary-dark); margin-bottom: 4px; }
.law-item .law-no { font-size: 13px; color: var(--primary); font-weight: 600; margin-bottom: 6px; }
.law-item p { font-size: 13.5px; color: var(--text-light); }

/* ---------- 页脚注 ---------- */
.footnote { font-size: 12px; color: var(--text-light); margin-top: 24px; padding-top: 16px; border-top: 1px dashed var(--border); line-height: 1.8; }

/* ---------- 响应式 ---------- */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .calc-layout { grid-template-columns: 1fr; }
}
@media (max-width: 860px) {
  .main-nav { display: none; position: absolute; top: var(--header-h); left: 0; right: 0; background: #fff; flex-direction: column; align-items: stretch; padding: 16px; gap: 6px; border-bottom: 1px solid var(--border); box-shadow: 0 8px 20px rgba(0,0,0,.08); }
  .main-nav.open { display: flex; }
  .main-nav a { padding: 11px 14px; }
  .nav-toggle { display: block; }
  .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .hero h1 { font-size: 30px; }
  .hero { padding: 52px 0 44px; }
  .compare-grid { grid-template-columns: 1fr; }
  .compare-vs { transform: rotate(90deg); }
  .site-footer .container { grid-template-columns: 1fr; gap: 24px; }
  .row-3, .row-4 { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 520px) {
  .row-2, .row-3, .row-4 { grid-template-columns: 1fr; }
  .hero-metrics { gap: 20px; }
  .section { padding: 40px 0; }
}